1. Field of the Invention
The present invention relates to an optical disc apparatus which performs the record and reproduction of an optical disc such as CD or DVD and which complements the data of the unreproducible part of the optical disc, and a data complementation method for the optical disc apparatus.
2. Description of Related Art
Optical discs, such as a CD (Compact Disc) and a DVD (Digital Versatile Disc) having a record capacity larger than that of the CD, have been extensively adopted as the record media of video and audio data. Besides, a BD (Blu-ray Disc) which is still larger in the record capacity than the DVD has recently been developed and commercialized. There has come into wide use an optical disc apparatus which records data by projecting a laser beam onto the optical disc medium, or which reproduces data by sensing reflected light from the optical disc medium.
The above optical disc apparatus utilizing the optical disc as the record medium includes an optical pickup which records information on the optical disc medium such as CD, DVD or BD, by projecting the laser beam of a wavelength corresponding to the sort of the optical disc medium, and which reproduces information by sensing the reflected light from the optical disc medium.
In a case where a flaw or the like exists in the record surface or substrate of the optical disc medium, the optical disc apparatus cannot accurately read out data. With the optical disc apparatus, in a case where the readout of the optical disc medium is impossible, the unreadable part thereof is read out repeatedly a predetermined number of times. In a case where the readout is nevertheless impossible, the unreadable part is omitted, and the readout is restarted from the next part, or the readout is ended after indicating to the effect that the readout is impossible.
In this regard, an invention stated in JP-A-2000-134583 discloses a technique in which compressed data obtained by compressing original data are retained in a separate area of an optical disc, and unreadable original data (damaged data) is complemented and corrected with the compressed data.
Meanwhile, some of data which are offered by employing the optical disc medium need to be revised or updated as in an encyclopedia, “karaoke” (prerecorded background music), a map, or the like. There has also been developed an optical disc apparatus of the type adapted for a network, by which such data requiring the revision or updating as are recorded within the recordable optical disc medium can be revised or updated through the Internet or the like.
In a case where the data which needs to be revised/updated exists in the optical disc medium inserted in the optical disc apparatus of the network adaptation type, this optical disc apparatus is automatically or manually connected to a server installed on the network to download revision/updating data, and record the revision/updating data on the optical disc medium additionally or record the revision/updating data in substitution for the data which needs to be revised/updated (refer to, for example, JP-T-2003-529118 where the term “JP-T” means a published Japanese translation of a PCT patent application, and JP-A-2002-49518).
The prior-art techniques, however, have had disadvantages as described below. In the case of the invention stated in JP-A-2000-134583, the compressed data for the complementation need to be possessed, and the record area of the optical disc becomes smaller to the corresponding extent. Besides, in a case where the damage of data has occurred in an optical disc which does not possess the compressed data beforehand, the data complementation cannot be performed, and the optical disc apparatus cannot reproduce the damaged data just like the conventional optical disc apparatus.
Further, the optical disc apparatus which revises/updates the data through the network can perform the revision/updating of the data in the case where the recordable optical disc is inserted, but it cannot record the downloaded data in a case where a read-only optical disc is inserted. In a case, for example, where an optical disc on which map data for a navigation system have been recorded is the read-only optical disc, the revision/updating of the data cannot be performed through the network. Besides, when the data to be updated by the network becomes large, the load of the network becomes heavy disadvantageously.